1. Field of the Invention
The present invention relates to the field of farming; more particularly, the present invention relates to a barn system that provides control of the environment inside a closed barn by monitoring conditions both inside and outside of the barn to provide complete animal comfort, in particular to milk cows, with evaporative cooling and improved heat concentration in the winter.
2. General Background and State of the Art
Farm animals, particularly milk cows, confined in a confined environment, are greatly affected by the conditions in the confined environment or barn. If the animals become stressed, the cows will produce less milk. Constant stress on the cows not only means less milk production, but it can also shorten their lives. A female calf takes approximately 24 months from birth to calving the first time, which brings her into her first milking (lactating) cycle. At that point, she is called a “first calf heifer.” She can be milked for 305 days and “dried” off (not producing milk for two months while she is in her last months of gestation, which uses a lot of energy maturing the calf inside of her). After the dry period, she calves again and is now in her second lactation. The cycle continues until something occurs which makes her an expense rather than an asset. This something is usually feet, leg, or udder disease problems. At this point, she is “culled” from the herd. The “cull rate” in California, for example, is 2.7 lactations, which makes the cow approximately 4.7 years old. She will have produced two or possibly three calves at that point. If the level of comfort for confined cows could be improved so that the cow's useful lifespan could increase by one year that would mean another year of milk production to the owner and probably an additional offspring, thus increasing the profitability of the owner's herd.
While the temperature and humidity in the barn affect the cow's comfort, another factor that can cause stress in a cow is the absence of light. Ideally, a cow confined in a barn should have about 18 hours of light and six hours of dark in a day. Many barns of known designs are dark, and so artificial lighting must be provided, thus raising the cost of power to the owner.
It is also known that for a milk producing cow in a confined barn that the cow should spend about four to six sessions of twenty minutes a day eating, followed by a period of walking around. For the most part, to maximize comfort for a cow, the cow should lie down much of the day. Any conditions in the barn that make the cow want to stand around and not lie down can impact the quality of life, milk production, and reproduction capability of the cow. Thus, control of the conditions inside a barn must be optimized for the comfort of the cows.
Conventional cooling livestock barns are generally of the “tunnel-ventilated” design. Such barns generally have a bank of fans mounted to the wall at one end of the barn that pull stale air from the barn and exhaust it to the atmosphere. As the stale air is pulled from the barn, fresh outside air is pulled into the barn through the opposite wall of the barn through evaporative pads, thereby adding moisture to the fresh incoming air and carrying the moisture into the interior of the barn. The inherent problem with such tunnel-ventilated barns is that the fresh air traveling through the evaporative pads absorbs water at an uncontrolled rate, which makes the effect of the “wet” air in the barn unpredictable and inconsistent, and thus making control of the humidity in the barn virtually impossible. Such designs can cause a great deal of stress to the livestock in the barn in the situation where the humidity is at an undesirable level.
Another conventional cooling barn design is the so-called “cross-ventilated” barn. A cross-ventilated barn is similar to a tunnel-ventilated barn, in the respect that the bank of fans on one wall of the barn exhausts stale inside air from the barn while fresh outside air is pulled through evaporative pads set on the opposite wall of the barn. However, in the cross-ventilated barn design, the exhaust fans and evaporative pads are set into the side walls of the barn, while in the tunnel-ventilated design, the fans and evaporative pads are set into the end walls of the barn. The side walls in these barns are closer to each other than are the end walls of the barn. Cross-ventilated barns are generally better than tunnel-ventilated barns, because the air inside the cross-ventilated barn tends to remain cleaner from contaminants because it travels a shorter distance through the barn. However, cross-ventilated barns tend to suffer from a different ventilation problem, namely, that the same amount of air traveling through the much larger surface of the side of the building, rather than through the much smaller surface area of the end of the building slows the airspeed considerably. This reduction in airspeed severely reduces the capacity of the air to remove water vapor from the cows, which is an important feature in maintaining the comfort level of the cows.
Conventional barns usually include misting or wetting devices to wet the cows when then are at their eating positions (barns generally have two distinctive cow feeding lanes near the long centerline of the barn). Under certain conditions, being positioned near such devices may be the most comfortable position for the cow. However, for the quality of life of the cows, standing in one place for prolonged periods of time is not healthy, and it may be that other cows will be denied access to the feeding lanes, causing further stress to the animals. Such a situation would mean that many of the cows could be left standing for prolonged periods of time, thus causing additional stress on the animals, which will likely result in lowered production of milk from the cows.
None of the conventional design of air distribution and air quality systems in barns includes controls that are impacted by conditions outside of the barn, such as outside temperature, outside relative humidity, wind direction, or wind velocity.
The conventional tunnel-ventilated and cross-ventilated barns also suffer from problems associated with resistance from headwinds on the outside of the barn. Depending on the direction and force of such headwinds, the ability to draw fresh outside air into the barn may be substantially reduced.
In conventional designs of barns, all of the air inside the barn must be cooled to avoid stratification and allow the air to be drawn out of the barn.
Recently, in some states, such as California, air quality standards for emissions from barns have become more stringent, thus requiring many owners of barns to install a means of cleaning the air that is exhausted from the barn.
It would be desirable, therefore, to provide a novel barn system for controlling the environment inside a closed barn that responds to conditions both inside and outside of the barn.
It would also be desirable to provide a novel barn system for controlling the environment inside a closed barn that provides a uniform circulation pattern of the air flowing in the barn that encourages the cows to follow their normal and desired patterns of eating, moving about, and laying down.
It would also be desirable to provide a novel barn system for controlling the environment inside a closed barn that avoids the problems associated with outside headwinds that are known to exist with conventional barn system designs.